Replication rolling back to normal.

Dear Team,

I have installed PostgreSQL 9.6 on two servers. One is master and other is
for slave server. Current setup as follows.

- Master Server - pgmaster
- Salve Server - pgslave

To implement this I have followed this article
https://www.digitalocean.com/community/tutorials/how-to-set-up-master-slave-replication-on-postgresql-on-an-ubuntu-12-04-vps

Master Slave combination is working fine.

when I create a file at the file trigger location ex:
/tmp/postgresql.trigger.5432 on *pgslave *server, it started accepting read
and as well as write request which is perfectly correct.

What I want to know is how to switch them back to the normal status. That
means pgmaster need to be the Master server which acept the writed and
pgslave that accepts only reads along with the replication.

Regards,

Dasitha.